The present invention relates to actuator assemblies for adjustment mechanisms of exercise machines.
The convenience, efficiency, and safety of weight-training exercise machines is widely recognized. Popular weight-training exercise machines feature multiple stations at which a user may perform a variety of exercises for developing and toning different muscle groups. For example, an exercise machine may include a xe2x80x9cpressxe2x80x9d station for exercising the chest and shoulders, a leg station for exercising the legs, and a pull-down station for exercising the arms and upper body. Typical exercise machines include a weight stack that can provide a variable load. The user simply adjusts the position of a pin to attach a desired number of lifted plates to a lift arm to achieve a desired training load.
FIG. 1 is an elevational view of an exercise machine 100 having a weight stack 102 and a press station 104. The press station 104 includes a lift arm 106 having a pair of handles 108. In operation, a user 110 may perform a press exercise by lying on a bench 111 and grasping the handles 108. The user then applies a training force to the handles 108, pressing the handles 108 upwardly away from the user""s chest. As the user 110 overcomes the gravitational force on the lifted plates, the handles 108 move upwardly.
Prior to performing the press exercise, the user 110 may adjust the position of the lift arm 106 to a desirable initial position. FIG. 2 is an enlarged partial isometric view of a press handle 108 and an actuator assembly 120 of the exercise machine 100 of FIG. 1. The actuator assembly 120 includes a gripper handle 122 pivotably attached to the lift arm near the press handle 108 by a pivot pin 126. A cable 124 is attached at a first end to the gripper handle 122. From the gripper handle 122, the cable 126 enters the interior of the lift arm 106, turns through a 90-degree turn 128 about a cable guide 127, and extends through the interior of the lift arm to an adjustment mechanism (not shown). The adjustment mechanism is attached to a base portion of the lift arm 106. When the user 110 depresses the gripper handle 122 in a downward direction 130 toward the press handle 108, the cable 124 is drawn upwardly and partially out of the interior of the lift arm 106. The adjustment mechanism is disengaged, freeing the lift arm 106 to be pivoted about the base portion into the desired position. Exercise machines 100 of the type shown in FIGS. 1 and 2 are commercially available.
The actuator assembly 120 has several disadvantages. For example, the cable 124 is prone to excessive wear and breakage. Because the cable 124 is wrapped about the cable guide 127 and turns through the 90 degree turn 128, considerable frictional forces are exerted on the cable 126 during actuation of the gripper handle 122. Over an extended period of time, the cable 126 is worn by the frictional forces and breaks. Also, because the gripper handle 122 only actuates in the downward direction 130, the gripper handle 122 is not easily actuated during some exercises that the user may perform using the press station 104. For example, when the user 110 stands facing the weight stack 102 with the lift arm 106 in a lowered position to perform a xe2x80x9cshrugxe2x80x9d exercise, the gripper handle 122 is not conveniently positioned for actuation, making it difficult for the user 110 to adjust the lift arm 106 to the desired position.
The present invention is directed to actuator assemblies for adjustment mechanisms of exercise machines. In one aspect, an actuator assembly includes a cable having a first end attached to the adjustment mechanism and a second end, a shaft rotatably coupled to the exercise machine proximate the second end, an actuating handle attached to the shaft, and a coupling member attached to the second end of the cable and engaged with the shaft. As the shaft is rotated, an actuating portion of the shaft pushes an engagement portion of the coupling member, tensioning the cable and actuating the adjustment mechanism. The actuator mechanism advantageously reduces wear and breakage of the cable. In another aspect, the shaft may be rotated in either a forward or an aft direction, improving the convenience of the actuator assembly for the user.